首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   5875篇
  免费   295篇
  国内免费   39篇
耳鼻咽喉   169篇
儿科学   336篇
妇产科学   193篇
基础医学   449篇
口腔科学   200篇
临床医学   499篇
内科学   1343篇
皮肤病学   109篇
神经病学   359篇
特种医学   204篇
外科学   1144篇
综合类   46篇
一般理论   5篇
预防医学   371篇
眼科学   219篇
药学   298篇
中国医学   12篇
肿瘤学   253篇
  2024年   4篇
  2023年   73篇
  2022年   118篇
  2021年   174篇
  2020年   115篇
  2019年   147篇
  2018年   162篇
  2017年   138篇
  2016年   225篇
  2015年   280篇
  2014年   307篇
  2013年   385篇
  2012年   542篇
  2011年   491篇
  2010年   271篇
  2009年   233篇
  2008年   394篇
  2007年   427篇
  2006年   335篇
  2005年   306篇
  2004年   303篇
  2003年   208篇
  2002年   233篇
  2001年   67篇
  2000年   46篇
  1999年   34篇
  1998年   22篇
  1997年   16篇
  1996年   10篇
  1995年   9篇
  1994年   8篇
  1993年   6篇
  1992年   10篇
  1991年   15篇
  1990年   10篇
  1989年   7篇
  1988年   6篇
  1987年   8篇
  1986年   8篇
  1985年   5篇
  1983年   7篇
  1979年   4篇
  1977年   2篇
  1975年   4篇
  1974年   4篇
  1973年   2篇
  1972年   2篇
  1971年   11篇
  1969年   5篇
  1968年   2篇
排序方式: 共有6209条查询结果,搜索用时 15 毫秒
31.
BACKGROUND: Apolipoprotein-E (ApoE) gene polymorphism has an important role in lipoprotein metabolism and could participate in the development of cardiovascular diseases (CVD). Plasminogen activator inhibitor-1 (PAI-1) is also regarded as a risk factor for CVD. The aim of the present study is to further investigate the possible link(s) between ApoE gene polymorphism and plasma PAI-1 antigen and serum lipid profile in peritoneal dialysis (PD) and hemodialysis (HD) patients. MATERIAL AND METHODS: We studied 72 PD patients (38 female, mean age 49.9 +/- 16.1 years), 72 HD patients (22 female, mean age 57.4 +/- 14.6 years), and 42 healthy subjects (21 female, mean age 50.1 +/- 18.6 years). Serum lipid parameters, plasma PAI-1 levels, and ApoE genotypes were determined in all subjects. RESULTS: The distribution of ApoE genotypes and alleles frequencies was similar in dialysis patients and healthy controls. In PD patients, total cholesterol (TC), low-density lipoprotein (LDL)-C, and ApoB levels were significantly higher than that of HD patients. HD patients with E3/4 genotype had elevated TC, LDL-C and ApoB levels compared with E3/3 genotype. TC and triglyceride levels were also higher in E3/4 genotype than that of E2/3 genotype. PD and HD patients showed a significantly increased PAI-1 levels compared with controls, whereas PAI-1 levels were highest in HD patients. There was no significant relation between ApoE genotypes and PAI-1 levels. CONCLUSIONS: The present study suggests that ApoE polymorphism significantly affects serum lipid profile in HD patients and epsilon4 allele carriers are more susceptible to have atherogenic lipid profile.  相似文献   
32.
33.
Background and aim. It has been demonstrated that right ventricular systolic dysfunction develops soon after surgical aortic valve replacement (s-AVR). While the impact of s-AVR or TAVI on the function of the left ventricle has been studied with various imaging modalities, little is known about the impact on right ventricular function (RVF). In the current study, we evaluated the impact of TAVI on RVF using conventional echocardiography parameters. Methods and results. Echocardiography was performed prior to 24 h, 1 month and 6 months after TAVI. RVF was assessed using (1) tricuspid annular plane systolic excursion (TAPSE); (2) RV Tissue Doppler Imaging (S’); (3) right ventricular systolic pressure (RVSP); (4) Fractional area change (FAC); and (5) RV ejection fraction (RVEF). TAVI was performed through the subclavian artery in two patients and femoral artery in 48 patients with an Edwards Sapien XT valve. TAVI was performed on 50 patients between the dates of December 2012 and June 2013. After TAVI, a statistically significant improvement was observed for all parameters related to RVF (RVSP, RVEF, TAPSE, FAC, RVTDI S’). During the 1st and 6th months this statistically significant improvement continued in TAPSE and FAC, and there was no deterioration in RVSP, RVEF, and RVTDI S during the 1st month but a statistically significant improvement continued in the 6th month. Conclusion. RVF assessed by conventional echocardiography did not deteriorate after TAVI in early and midterm follow-up. Further, TAVI provides improvement of RVF and can safely and efficiently be performed in patients with impaired RVF.  相似文献   
34.

INTRODUCTION

Giant cervical and mediastinal goiter may lead to acute respiratory failure caused by laryngotracheal compression and airway obstruction. Here, we present a case admitted to the emergency service with a giant goiter along with respiratory failure and poor general health status, which required urgent surgical intervention.

PRESENTATION OF CASE

A 71-year-old female admitted to the emergency room with shortness of breath and poor general health status resulting from a giant cervical swelling progressively increased during the last 7 years and constituted severe respiratory failure which has become severe in the last one month. A giant nodular goiter of the left thyroid lobe extending retrosternally, causing tracheal compression, limiting the neck movements was detected with clinical examination and bedside ultrasound. Emergency thyroidectomy was planned. Fiberoptic-assisted awake nasal intubation was performed in the operating room. Emergency total thyroidectomy was performed for the life-threatening respiratory failure. Postoperative period was uneventful. She was transferred from intensive care unit to the ward on postoperative day 3 and was discharged from the hospital on the postoperative 7th day. Benign multinodular hyperplasia was reported on the histopathological report. Patient was included in routine follow-up.

DISCUSSION

In the present case tracheal destruction due to compression of the giant goiter was found in agreement with previous reports. Emergency thyroidectomy was performed after awake intubation since it is a common surgical option for the treatment of giant goiter causing severe airway obstruction.

CONCLUSION

Respiratory failure due to giant nodular goiter is a life-threatening situation and should be treated immediately by performing awake endotracheal intubation following emergency total thyroidectomy.  相似文献   
35.

Background

Seroma is a frequent problem after mastectomy (ME) and axillary lymph node dissection (ALND). Seroma is associated with pain, discomfort, impaired mobilisation and repeated aspirations, often resulting in a surgical site infection (SSI). It has already been demonstrated that minimizing dead space through fixation of the skin flaps to the underlying muscles (quilting) lowers the incidence of seroma. The aim of this study was to evaluate the effect of quilting on the incidence of seroma, and SSI.

Methods

Two consecutive groups with a total of 176 patients following ME and/or ALND were retrospectively compared. Endpoints were the incidence of seroma, and number and volume of aspirations and SSIs. Analysed risk factors were age, ME, lymph node dissection, neoadjuvant therapy, body mass index (BMI) and hypertension.

Results

The quilted group (n = 89) scored significantly better on all endpoints compared with the conventional group (n = 87). The incidence of seroma decreased from 80.5 % to 22.5 % (p < 0.01), the mean number of aspirations from 4.86 to 2.40 (p = 0.015), the volume of aspirations from 1660 ml to 611 ml (p = 0.05) and the SSIs from 31.0 % to 11.2 % (p < 0.01). Increasing age and lymph node dissection were found to be risk factors for seroma; quilting was a protective factor.

Conclusion

Quilting is an effective method for preventing seroma and its complications.  相似文献   
36.

Background

Distal Achilles tendon avulsions are in the form of either bony and nonbony avulsion of Achilles tendon from its calcaneal insertion.

Methods

Four patients with distal Achilles tendon avulsions or ruptures which were treated with tendon to bone repair using suture anchors are presented here. Operated leg was immobilized in above-knee cast for 4 weeks while the patient walked non-weight-bearing. Then, cast was changed to below knee, and full weight-bearing was allowed. Patients underwent gait analysis minimum at first postoperative year.

Results

Mean American Orthopedics Foot Ankle Society ankle/hindfoot score of patients at last visit was 88.75 (range 85–100), and Achilles tendon total rupture score was 77.75 (range 58–87). Mean passive dorsiflexion of injured ankles (14° ± 5°) was lower than uninjured ankles (23° ± 9°). All the kinematic parameters of gait analysis were comparable to the uninjured side. Maximum plantar flexion power of injured ankle was 1.40 W/kg, and this was significantly lower than the contralateral side value 2.38 W/kg; (P = 0.0143).

Conclusions

There were no visually altered gait or problems in daily life. Suture anchor tenodesis technique of distal Achilles tendon avulsions was successful in achieving durable osteotendinous repairs.  相似文献   
37.
The aim in this study is to evaluate predictive factors on sperm retrieval and pregnancy rates by microdissection testicular sperm extraction in non obstructive azoospermia patients with a history of orchidopexy operation. A total of 148 patients were included, and their medical files were evaluated. Data related to possible predictive factors on sperm retrieval and pregnancy rates such as age at orchidopexy operation, unilateral or bilateral presence of undescended testis before orchidopexy, testis volumes and hormone levels were statistically analysed. It revealed that the mean ages in patients with unilateral and bilateral orchidopexy operations were 35.37 (±4.84) and 33.94 (±5.91) respectively. Mean testis volume in the unilateral orchidopexy group was 7.59 (±3.12) ml on the right testis and 7.37 (±2.86) ml on the left testis. Mean FSH levels were detected as 22.71 (±11.86) mIU/ml in the unilateral group and 28.19 (±12.40) mIU/ml in the bilateral group. In our study, we have shown that the age at which patients undergo orchidopexy and the unilateral or bilateral presence of cryptorchidism has no correlation with sperm retrieval and pregnancy rates.  相似文献   
38.
In this study, the effects of the wound‐covering materials, Acticoat® and Cutinova Hydro®, on wound healing have been studied in rabbit models with open and tissue‐lost wounds with full‐thickness flank excisions. Rabbits were used as subjects with three groups of four rabbits each, and trial periods of 7, 14 and 21{\uns}days. Four circular wounds, of 1.5 cm diameter were made two on the right (one of them control) and two on the left (one of them control) of the dorsal sides of the abdomen. Acticoat® and Cutinova Hydro® were applied on the wounds with suture for a period of 21 days and one each placed on the right and left sides as control with gauze. Biopsy specimens were taken from the animals at the end of the research period to check the length of the epithelium, epithelial thickness, size of wounds, wound granulation tissue formation and histopathological evaluation for clarity. The Acticoat® group showed better healing and scar formation compared to the Cutinova Hydro® group by macroscopic examination. Epithelial wound length and clarity in terms of statistical difference occurred on day 21 (P <0.05); while the length of the wound epithelium decreased patency, epithelial thickness on days~7, 14 and 21, showed no statistical differences (P >0.05). As a result, the Acticoat® wound dressing was determined as a more reliable for the early wound healing. This study has shown the short‐term clinical benefits of hydroactive, polyurethane dressings in the management of acute wounds. However, longer periods of wound healing procedure should be planned for reliable and safe results of wound dressing. It has also been concluded that microbiological analyses should be included for more robust and reliable comparisons.  相似文献   
39.
OBJECTIVE: The analgesic effect of bupivacaine/fentanyl with epinephrine given interpleurally after thoracotomy was investigated in a randomized placebo and intravenous controlled study. DESIGN: Prospective clinical study. SETTING: University teaching hospital. PARTICIPANTS: Sixty American Society of Anesthesiologists physical status II and III patients scheduled for posterolateral thoracotomy with general anesthesia. INTERVENTIONS: Patients were randomly divided into 4 groups to receive either 0.5% bupivacaine/1.5 microg/kg of fentanyl with 5 microg/mL of epinephrine (n = 15, group IPBF), 0.5 % bupivacaine with 5 microg/mL of epinephrine (n = 15, group IPB), or saline (n = 15, group IPS) in a total volume of 15 to 20 mL in 60 seconds by an interpleural catheter placed at the end of surgery by direct vision. The same volume of bupivacaine 0.25% and 1.5 microg/kg of fentanyl with 5 microg/mL of epinephrine to group IPBF, bupivacaine 0.25% with 5 microg/mL of epinephrine to group IPB or saline to group IPS was injected through the interpleural catheter every 6 hours for 48 hours postoperatively. Intravenous fentanyl (n = 15, group IVF) and interpleural saline groups received 1.5 microg/kg of fentanyl intravenously at the first complaint of pain. All patients also received patient-controlled analgesia (PCA) with fentanyl for 48 hours postoperatively. Metamizol sodium was used as a rescue analgesic. MEASUREMENTS and MAIN RESULTS: Adequacy of pain relief was evaluated with the "Prince Henry Pain Scale" and visual analog pain scale. Fentanyl consumption via PCA and complications were evaluated for 48 hours. Visual analog scale scores were significantly higher in the interpleural saline group at 4 and 12 hours (6.6 +/- 1.2 and 5.0 +/- 2.1, respectively) postoperatively. Significantly more patients in the IPBF group had lower pain scores during coughing and deep breathing. Fentanyl consumption via PCA device was significantly higher in the intravenous fentanyl group (1,069 +/- 96.9 microg) than the interpleural groups (577.3 +/- 72.2 microg, 651.1 +/- 61.9 microg, and 601.0 +/- 22.6 microg in IPBF, IPB, and IPS groups, respectively). CONCLUSION: It is concluded that total fentanyl consumption via PCA decreased in all interpleural groups, but pain during coughing and deep breathing was significantly reduced in only the interpleural bupivacaine/fentanyl with epinephrine group.  相似文献   
40.

Background

Central pancreatectomy is a definitive treatment for low-grade tumors of the pancreatic neck that preserves pancreatic and splenic function at the potential expense of postoperative pancreatic fistula. We analyzed outcomes after robot-assisted central pancreatectomy (RACP) to reexamine the risk–benefit profile in the era of minimally invasive surgery.

Methods

Retrospective analysis of nine RACP performed between August 2009 through June 2010 at a single institution.

Results

The average age of the cohort was 64 (range 18–75 years) with six women (67 %). Indications for surgery included: five benign cystic neoplasm and four pancreatic neuroendocrine tumor. Median operative time was 425 min (range 305–506 min) with 190 ml median blood loss (range 50–350 ml) and one conversion to open due to poor visualization. Median tumor size was 3.0 cm (range 1.9–6.0 cm); all patients achieved R0 status. Pancreaticogastrostomy was performed in seven cases and pancreaticojejunostomy in two. The median length of hospital stay was 10 days (range 7–19). Two clinically significant pancreatic fistulae occurred with one requiring percutaneous drainage. No patients exhibited worsening diabetes or exocrine insufficiency at the 30-day postoperative visit.

Conclusions

RACP can be performed with safety and oncologic outcomes equivalent to published open series. Although the rate of pancreatic fistula was high, only 22 % had clinically significant events, and none developed worsening pancreatic endocrine or exocrine dysfunction.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号